#!/usr/bin/env python3

import sys, re


def show(mp):
    for line in mp:
        print(''.join(line))


def easter_egg(robots, w, h):
    for steps in range(7000, 10000):
        print('Steps: ', steps)
        m = [['.'] * w for _ in range(h)]
        for r in robots:
            px, py, vx, vy = map(int, r)
            nx = (px + steps*vx)%w
            ny = (py + steps*vy)%h
            m[ny][nx] = 'X'
        show(m)


if __name__ == '__main__':
    robot = re.compile(r'p=(?P<px>-?\d+),(?P<py>-?\d+) v=(?P<vx>-?\d+),(?P<vy>-?\d+)')
    robots = [robot.search(line.strip('\n')).groups() for line in open(sys.argv[1])]

    # space: 11 x 7 for example and 101 x 103 for real input
    w, h = 101, 103
    steps = 100
    q1, q2, q3, q4 = 0,0,0,0
    for r in robots:
        px, py, vx, vy = map(int,r)
        nx = (px + 100*vx)%w
        ny = (py+100*vy)%h
        if nx in range(0, w//2):
            if ny in range(0,h//2): q1 += 1
            if ny in range(h//2+1,h): q2 += 1
        if nx in range(w//2+1,w):
            if ny in range(0,h//2): q3 += 1
            if ny in range(h//2+1,h): q4 += 1

    # challenge 1
    res1 = q1 * q2 * q3 * q4
    print(f"challenge 1:\n{res1}\n")

    # challenge 2
    easter_egg( robots, w, h)
    res2 = "8006" # empirical solution
    print(f"challenge 2:\n{res2}")